primitive shed door

I’m building a koi pond and I needed a filter house. This is the door I put on the filter house. Simple and works great. I used P.T. 2×12 biscuit joined and then lapped with 1×6s, glued and screwed. Door latch works by sliding the knob left/right. Silly wooden fish covers the slot. I looked at a lot of primitive door latches and was surprised to not see one quite like this. I didn’t need it to be completely weather tight. I just needed something to keep the critters out. The building is completely covered in earth except for a retaining wall around the doorway and there are no windows. So I put in a “telescope” vent pipe on one end and drilled a hole in the door for some ventilation. And door is hardly sealed too. I covered the hole on the outside with the cast iron fish raised up about 1/2”. And the screen is to keep bats and squirrels out.